Genkai Tokki: Castle Panzers

In a certain country, there was a coup detat. The princess, who barely managed to escape, meets the protagonist when he appears before her. However, in protecting the princess party, the protagonist is surrounded by enemies and falls into a dilemma. Then, he hears a mysterious voice. “Do you want… power?” The protagonist has no choice but to respond. Upon doing so, a mysterious castle somehow emerges from the ground. Its power overwhelms and repels the enemy. Then, the mysterious creature Otton ...